Australian actor Hugh Jackman turned real-life action hero at Sydney's Bondi Beach on Saturday, when he helped his son and another man to safety from strong currents in the surf.

Jackman is shown linking hands with a man and pulling him from a fast-flowing channel on to a sandbar, where the water is shallow, in television footage broadcast by the Nine Network. The network said Jackman later helped his own son, Oscar, 15, from the same current.

Peter Adam, who told Nine he was the man Jackman helped, said he wasn't rescued by the film star.

"He wasn't rescuing me, I was assisting him to get his daughter up to the sandbar. He then grabbed my hand to get us up," Adam said.

The actor is also shown beckoning other swimmers to shore, away from a rip current flowing out to sea.

Jackman was at the beach with his family, Sydney's Sunday Telegraph newspaper reported. Witness Lynzey Murphy told the paper that surf conditions changed quickly, but that Jackman stayed calm.

"When we got in the water 20 minutes earlier it was fine. Then the water just came up suddenly," she said.

"Hugh just pulled them calmly on to the sandbar. He then said: 'All right, we are going to walk towards the flags.'"

A lifeguard told the paper that the beach was later closed because of dangerous surf.